Similar to IPv4 arp protection support, this patch adds the necessary OVS
rules to prevent ports attached to agent from sending any icmpv6 neighbor
advertisement messages that contain an IPv6 address not belonging to the port.
For details please refer to "Figure 3. Attack against IPv6 Address Resolution"
http://www.cisco.com/web/about/security/intelligence/ipv6_first_hop.html
DocImpact
SecurityImpact
Closes-Bug: #1491690
Change-Id: I1f8311f1b9ae1be02afde3e9078e49c6da373a88